Heating element



M. SCHEY.

HEATING ELEMENT.

APPLICATION HLED AuG.29x92|.

1,422,879, Patented July 1l, 1922.

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UNITED STATE MAX SCHEY, 0F BROOKLYN, N EW YORK.

HEATING ELEMENT.

Application filed August 29, 1921.

T o all 'whom t may concern Be it known that I, MAX SGHEY, a citizen oi the United States, residing at New York city, borough of Brooklyn, county of Kings, and State of New York, have invented a certain new and useful Heating Element, ot which the following is a specification.

This invention is a heating element adapt ed particularly for rotisseries, the name applied to the Well known broiling apparatus made under Patent No. 902,724 of George Giovanna.

Rotisserie-s of the character specified embody a plurality of spits arranged one above the other and extending in horizontal position before an upright or vertical heating element, constituting the source of radiant heat. which is employed for the roasting or broiling of meats supported on the spits.

The Giovanna patent referred to shows a coal fire back of a vertical grate to furnish heat for roasting meats supported on spits positioned forwardly thereoil and one above the other. This method of broiling was practised for a number of years, but, as coal fires give off objectionable gases` smoke, require proper drafts, and are difficult to main tain at a proper temperature, a series of experiments were carried out to the end that gas might be adopted as a fuel, in lieu of the coal.

These experimentations, which l carried out, with the problem under consideration lead me to the conclusion that for efficient broiling, the best results can be obtained through the employment of a radiant and preferably radiated heat and not by the direct heat of a flame. Having come to this conclusion. experiments were carried out with heating elements embodying asbestos libre or asbestos wool, as it is sometimes called. This wool or fibre was tufted on the face ot a plate provided with perforations through which the gas found exit and burned on the face of the plate, the object being to raise the asbestos fibre to a high temperature, so that the heat thereof might be ra, diated and such radiated heat employed for the cooking operation. Such a structure was found, when new, to give superior results in effecting a relatively slow cooking and simultzuieous broiling or browning of the meats.

It was found, however', that since the heating element for a .broiler is more or less directly subjected to fait from the roasts which Specification of Letters Patent.

Patented J nly 11, 1922. Serial No. 496.263.

is splashed or otherwise comes in contact with the heating element, that after a relatively short time, the asbestos Wool or fibre became more or less impregnated with such fat, which seemed to act as an insulator with the result that such fibre did not heat propeily and consequently did not radiate the heat to efficiently effect the cooking operation. Moreover. such fat impregnated fibre emitted objectionable odors` and smoke which are highly detrimental.

ll'ith asbest-os fibre, it was practically impossible to clean or free the same from the fatty content. and, accordingly, asbestos fibre for the purpose specified has proven impractical. i

lith these considerations in mind, the present invention embodies. in its broadest aspect. the use of hardened plastic mineral earth asa radiating medium for heatapplied directly thereto and` experience has shown that when this material is :used in the making of a rotisserie burner, that high efficiency in heat radiation is accomplished and at the same time the burner retains such efiiciency, cven though if be spattered with fat. Moreover, 'fat may -be readily removed from the burner by cleaning the same, since thc mineral earth is relatively non-porous. so that the soaking of the tagt into the ma terial is not possible.

lu practically carrying out the invention, I preferably employ' what is known in the trade as asbestos wood as a backing or foundation for the burner. This asbestos Wood is a combination of asl'iestos, cement, and a suitable binder and is a commercial product employed in the buildingntrades for other uses. It is hard and rigid and is not apt to sag. warp or twist under heat. 0n the face of this plate, which is preferably stippled or roughened. are molded parallel, horizontal ribs or ridgesV of plastic mineral earth, sometimes known to the trade. as retort cement, because of Sits well known properties of resisting heat which recommends it for use as a lining for retorts, wherein it serves to protect the metallic Wall of the retort from the direct action of the heat. These parallel ribs are molded directly on one face of the asbestos wood plate and While in plastic form, are preferably gone over with a sharp implement or trowel and fashioned into uneven surfaces Yor sharp irregularities or points, which, vin the operation ot' the burner, are adapted to be heated to a high temperature, and, because of their relatively large superficial area effect a maximum radiation of such heat.

Across the back of the plate and in spaced relation thereto is a metal plate forming between said plate and the face plate of the burner a gas chamber into which gas is introduced and from which it flows through rows of perforations positioned between the ribs or ridges of the mineral earth on the front of' said plate. The gas burns forwardly of the plate at each perforation in a small blue flame, which serves to heat the mineral earth for the purposes specified.

The invention embodies further features of construction, which are impoitant in the practical operation of the burner and these features will be clearly brought out in the following detailed description and in the appended claims.

The accompanying drawings illustrate one practical embodiment of the invention` but the construction therein shown is to be nnderstood as illustrative, only. and not as defining the limits of the invention.

- Figure 1 is a front elevation of one lateral halt of a burner embodying the present invention.

Figure 2 is a, back elevation of the structure shown in Figure 1.

Figure 3 is a. central section perspective of the burner; and,

Figure 4 is a true section on the line 4-4 of Figure 2.

Referring to the drawings, 1 designates the front plate of a burner, which may he generally referred to as fire-proof, non-metallic and rigid. It may satisfactorily embody a slab of asbestos wood, the name given by the buildingr trades to slabs of composition Cement and asbestos commonly used iu such trades for partitions, walls. ceilings, etc.. as a backing for plaster. This material is lire-proof and very rigid and does not twist or'warp under heat.

In the back of the face plate l is positioned a haelt platel 2 preferably of metal and off-set intermediate its margins to form a gas chamber 3` into which gasmay be introduced through an inlet nipple 4. secured to the hack plate by rivets 5. The marginal portions of the back plate 2 are adapted for fare engagement with the back of the front Aplate 1 and a U-shaped binding 6 embraces the margins of both the front and back plates, throughout the four sides of the-burner. for the purpose of binding the parts firmly together, so that they may be handled asa unit. l u n Formed in the iront plat-e 1 are a plurality of perfor`ations 7. These perforations arey arranged inV horizontal rows extending' transversely of the burner and spaced apartl vertically. TheyV are preferablyformed bv drilling the Plate 1, and, in practice, I lin-d that they will function to great-er advantage il' each perforation is countersunk at its hack as shown at 8, since when so formed thereis less liability o l'V choking the perforations,y which are necessarily quite small, by impurities which ma)y be carried in suspension by the gas, and. l'urtlicrinore-` lint or particles of' asbestos will not serve to close the periorations so readily as would he the rase ii' the holes were drilled straight through for the l'nll thickness of the plate. The coimtersinking ol' the perforations has been foundV in practice to obviate considerable trouble ordinarily experienced.

Extending horihontally across the Afare of the plate 1 and intermediate the successive rows of perfora-tions T are molded ribs 9. These ribs are formed from plastic mineral earth. known to the trade as retort cement, and generally used to line thi` metallic casingrs ol' retortsl` so as to protect them against the direct action of the fire. The mineral earth is applied to the face of the plate l in a plastic condition and the 'fai-e of said plate is preferably roughened or stippled so as to permit of a proper bond with theY plastie material. The ribs 9. after being moldeiL or otherwise applied to the Vplate 1, are rougl'iened in any suitable manner, such 'lor example as by a sharp instrument so that the surfaces will be uneven and preferably .lirif-itlingir With sharp projections 'or points giving a very irregular and: uneven appearance. The effect of this operation is to impart tothe ribs maximum superficial area and at the same time provide through the employment of sharp points and knifelike edges for maximum radiation.

After the ribs are applied' inthe manner describedLthey are allowed to harden and thereafterbecome extremely hard and non-porous. f y

lith the construction described.v the gas is introduced into the chamber Ci. issuesfrom the perlorations 7 and burns with Va blue llame forwardly 'oi the face plate.Y These smallblue dames raise the ribs 9 to a high temperature. the heat whereof is radiated to the `meats supported onspits forwardly of the burner which stand in uprighhsubstantially vertical position.

ln practice, the gas pressure is 'sofregulated that the Hemos are maintained relatively small and Vjustsuliicient toV properly heat the ribs 9, so that the heat applied to the roasts is purely a radiated heat and' is in every respect a radiant heat. According-ly. the roasts are notV burned Vas would apt to he the case through' a directiheat,` but. in contradistinction. are baked through by the time their outer surface has acquired the desirable rich brown color. Y E

Tt Willbe noted particularly from Figures 'and 53 of the drawingsrthat' the gas is introduced into the gas chamberat the lower that it has a tendency to ,rapidly rise inthe chamber and flow with the greatest fonce through rthe upper rows of peroraytions. y1 have discovered, .however,ithat if Wiiiretgauge screens are positioned faerossthe gas @ham- -f ber, so as lto extend horizotaillytheywonm barriers tothe gaswhich serre :to ,retard the` upward flow thereof, so that Athea-gas 4is .applied iniequal quantities and underanequai pressureto all rows of perforations.` These screens are designated l0 in the drawings,

and while they may beisecuned :imposition iin any suitable manner, theyxare preferably held -in place by bolts 11, which pass throughA the face plate and thnoughfrthe baclry plate,

i afterffthe manner best 'show-'afin A' further advantage in the employment of the screens l() is vthat they precludeflash-l backs of lire. since the `flash-baelrs'iwiil hot oocur through a nvire screen. They ffulfitherl l serve te it'ree kthe gasof impart-'ities in l'susliwn-iion therein. The loweimostsreen is preferably downwardly extended'lftdsuolir degree-as to oofver the ifieedfnippiee 4,-ais ibst shown in Figure 3, so astorstfsainatheima coming gas.

The purpose of the bolts 11 is to rigidly tie together the front and back plates inwardly of their margins and a spacing member i2 preferably surrounds each bolt between the plates` so as to maintain said plates at all times in proper spaced parallel relation.

In some of the prior burners placed on the market. the front plate has been formed of relatively pliable asbestos. which, when subjected to heat, expanded and warped usually in the direction of the back plate, so that the gas chamber was not of uniform depth throughout. This condition eil'ected an uneven distribution of the gas due to venturi principles` but it will be manifest from the foregoing description of the present invention that this cannot occur in the construction described` not only because of the introduction thereinto of spacers, but also because of the rigid character of the face plate l. In practice, the bolts 11 are preferably stove! bolts with countersunk heads and are so positioned that their heads will lie beneath and be covered by the ribs 9, so that they are properly protected from the heat and `will not be unduly subject to expansion.

One of the most deleterious conditions surrounding prior burners is that after they have operated a short time. they become more` or less blanketed by floating gases due to improper or incomplete combustion. These gases whirh usually are of the poisonous variety. blanket the fare of the burner` against the inflow of pure air which it is required to effect complete combustion. during the continued operation of the burner,

and produee relatively long yellow dames whichwliot `only cause a deposit of carbon, but zure lnighly :ineHicient .forheati-ng purs poses; f i

i. fiitfith. the -biirnergottlie pre-sent invention,

beweren, .the radiatiien. is so aetive that there is a strong current of heeft passing away from the burner which noty only precludes blaaiketing of the burner., lbut also .precludes aconstantlinirush of fresh air,.proeluciiig completepoombustion and proper heating;

Y Havingithus fully described theinvention-Z` what llnlaimas new and desire to secure by Letters .Patent is: i

A 1.V A heatingY element for broilers embodyiingfa rgidginoninflammable and nenmetarllic plate provided withV flat ,fases and nharing parallel rowsoit perforationsall :of which peil-afbrations` arei'iof substantially the saaie size` :and ,three-gh which i 'gas' 1is adapted. te prassi,-land parallelfribs of hardened plastic mineral #earth .molideddirectly on to one face ein the; platewand p'osiitisied Vbetxiveen i succes-` sifue f mwsof ipenferatiomsi I :whereby gas is suing: inem `thefperoraltionsY"is adapted to burn between the ribs and heatsaid eihsto a ,rliiiigh: itempieratnre,` so rthat the iheaft Atalteu upnby tbe-'ribs magiibe radiated i v f 1 2. A heating element for broilers embodying a rigid, nonmetallie and noninilammable plate provided with a plurality of parallel rows of perforations through which gas is ada ted to pass, a plurality of ribs of hardened plastic mineral earth molded directly on the face of the plate and between Successive rows of perforations, said plate being placed so that the ribs are in hori- Zonta] positions, whereby gas issuing from the perforations at the ribbed face of the plate, burns between successive ribs and the flame is deflected away from the face of the plate in such manner as to preclude the llames of one row of perforations from interfering with the proper combustion of the gas owing from the superimposed rows of perforations.

3. A heating element for broilers embodying a rigid, noninflammable and nonmetallic` Aplate. provided With'a substantially flat face and perforated to permit the passage of gas therethrough, and projections extending from the face of the plate and formed of hardened plastic mineral earth, whereby the flame from the burning gas is adapted to heat said projections to a high temperature so that the heat thus taken up by the projections may be radiated to effect the broilin operation.

4. A eating element for broilers embodying a rigid, noninflammable and nonmetallic plate provided with dat faces and having parallel rows of perforations through which gas is adapted to pass, and parallel ribs of hardened plastic mineral earth molded directly on one face of the plate and positioned between successive rows of perfora-I tions, whereby gas, issuing from said perforations,` is adapted to burn Ibetwee'n the ribs for the purpose of heating the same'to a high temperature, so that the heat` thus taken up by the ribs may be Tadi'atedto effect the broiling operation.

5. A heating element for broilers embodying a rigid, noninlammable and nonmeta-llic plate provided with flat faces and having parallel rows of perforationsthr'ough which gas is adapted to pass, and parallel 'ribs of hardened plastic mineral earth molded directly on one face of the plate and positioned between successive rows of perforations, whereby gas, issuing from said perforations, is adapted to burn between the ribs-for the purpose of heating thesame to a high temperature, so that the heat thus taken up by the ribs may .be radiated to effect the broiling operation, said ribs being provided with a roughened and uneven surface comprising relatively small tapering projections, which increase the superficial area of said ribs and increase its capacity to radiate the heat.

6. A heating element for broilers'embodying a perforated face plate, a back plate spaced from the face plate to form a gas Chamber, a gas inlet to said chamber at the lower portion thereof, and a plurality of screens positioned transversely across the gas chamber for the purpose of retarding the flow of gas through the gas chamber and effecting a uniform distribution of said gas through all of the perforations.

7. A heating element for broilers embodying an opstanding face plate provided with spaced horizontal rows of perorations.y substantially parallel rows of hardened plastic mineral earth molded on the forward Vface of the face plate intermediate the rows of perforations, a back plate spaced from the front, plate to provide an intermediate gas chamber, a gas inlet at the lower part of the gas chamber, and foraminous partitions extending transversely of the gas chamber and in the path of the flow of gas upward through said chamber for the purpose of retarding the upward rush of gas and assuring its uniform distribution to all of the perforations.

In testimony whereof I have signed the foregoing specification.

MAX SCHEY. 

